Answer:
At the bottom you have the producers aka auto trophic livings (which use inorganic compounds to grow, produce energy, matter and so on..). These organisms would be plants, Cyrano bacteria, over all any organisms that do photosynthesis.
Microbes. Bacteria, for example, convert nitrogen and carbon dioxide from the air into usable components that plants and animals can use as essential building blocks. A loss of all microbes would be terrible news for living organisms that can't create or take in these essential nutrients on their own.
Species selection. Species selection is the process by which intrinsic biological characteristics in organisms change depending on the type of environment they're interacting with. In this case, the subsequent generations of the fly lost the ability to fly because their environment didn't require them to use wings for survival, hence they stopped growing them and subsequently lost the ability to fly.
The type of bond formed between carbon and hydrogen is NON POLAR COVALENT BOND.
Covalent bond involves sharing of atoms between two elements; each element will donate electrons which will be equally shared by the elements involved. In the case of carbon and hydrogen, carbon has four electrons in its outermost shell, therefore it will form a covalent bond with four atoms of hydrogen each of which will donate one electron.